1. Field of the Invention
The invention relates to a bi-stable display, and more particularly to an alignment structure of the bi-stable display.
2. Description of the Related Art
As the progress of the display technology, liquid crystal display (LCD) has been widely applied to various consumer-electronic products, such as cellular phones, portable computers, digital still cameras (DSC), portable navigation device (PND) and so on. However, the e-paper technology has been risen with respect to the requirement of thin package, low power consumption and long life time.
Take the electrophoretic display (EPD) developed by E-Ink company for instance, it includes a front plane laminate and a thin film transistor (TFT) array substrate wherein the front plane laminate includes a common electrode and a display layer. The display layer includes a plurality of microcapsules and charged black and white particles capable of being moving within the microcapsules by the voltage difference between the common electrode and a pixel electrode of the TFT array substrate to provide grayscale images. However, the inaccurate alignment between the front plane laminate and the TFT array substrate would result in inferior images and the entered moisture resulted from the package shift would decrease the yield rate.
Refer to FIG. 1 which illustrates a sectional view of the alignment structure of the electrophoretic display disclosed in the patent with published number TW 200628954. The electrophoretic display 100 includes a plurality of microcapsules 111 disposed on the upper substrate 110 wherein each microcapsule 111 is comprised of a side wall 112 and a seal layer 113 to hold the dielectric fluid 114 and multiple charged electrophoretic particles 115. The electrophoretic particles 115 are moved within the microcapsules 111 by the voltage difference between a common electrode 116 of the upper substrate 110 and a plurality of pixel electrodes 121 of the bottom substrate 120. With respect to the alignment structure, each side wall 112 on the upper substrate 110 has a first position structure 117 and the bottom substrate 120 has a second position structure 122 corresponding to the first position structure 117 thereby forming a complementary saw tooth configuration for the alignment of the electrophoretic display 100.
Nevertheless, the first position structure 117 and the second position structure 122 are formed through punching or rolling process such that the manufacturing cost would be increased. Therefore, providing an alignment structure with both alignment and inspection function based on the conventional process becomes the target of the present invention.